1. Field of the Invention
The present invention relates to fluted filter media, and in particular, to fluted filter media having flutes which minimize restriction across the filter.
2. Prior Art
Pleated filters which utilize filter media to remove contaminants from fluids are commonly known and take on many configurations.
A common problem with filters is inadequate filter surface area. Prior attempts to improve filtering surface area for a given filter volume have not been entirely successful. Pleated filters are commonly used which utilize a pleated filter media in an attempt to overcome this shortcoming. Although pleated filter material may increase the filter area, as the pleats are placed closer and closer together, thereby placing more and more filter media in a given volume, the pleats are pressed tighter and tighter together, thereby restricting the flow. This restriction may cause the velocity of flow to increase in order to pass through the filtering media, thereby increasing the pressure differential across the filter which may cause additional problems in the system.
Most permeable filter media does not provide structural support so that the filters require housings for supporting the filtering material. This increases manufacturing costs as well as the mass and size of the filter.
To improve restriction and provide increased media area, as well as filter efficiency, fluted filter configurations may be utilized. Fluted filters have the capability of increased media area per unit volume, as well as less restriction and substantially straight-through flow.
Although fluted filters provide improved flow characteristics and efficiency over prior filter designs, fluted filters have the possibility of greater efficiency and improved flow characteristics. The sealed upstream ends of flutes provide a substantial blockage of the flow, and when combined with the filter material, more than half of the available cross sectional area of the fluid flow is blocked. Filter designs which have greater cross sectional area transverse to the flow provide improved flow and restriction characteristics.
It can be seen that new and improved filters are needed which provide self support, improved restriction, improved flow characteristics, and greater efficiency. In particular, fluted filters should have a leading edge which provides less resistance and takes up less of the cross-sectional flow area than standard flute designs. In addition, the cross-sectional area of the filter media and the closed ends of the flutes at the upstream edge should be smaller than the opening area at the upstream edge of the flutes. Such improved filter designs should also be easily manufactured without undue additional steps. The present invention addresses these as well as other problems associated with filter designs.